The present invention relates to a microprocessor system having a cache directory and a cache memory and, more particularly, to a microprocessor system in which the cache directory is initialized not by software but by hardware.
In recent times, the increase in the processing speed of microprocessors has given rise to strong demand for a corresponding increase in the memory-access speed. If the memory-access speed is not sufficiently increased, it then becomes the determining factor as regards the processing speed of the entire microprocessor system. A conventional solution to this problem is to use a cache memory. In this case, however, the cache directory must be initialized before it can be used.
Conventionally, in a microprocessor system incorporating a microprocessor which does not include a cache memory control section, the cache directory is initialized by means of software. However, when software is used to initialize the cache directory, compatibility between programs cannot be achieved, since an existing program will not normally include this software. For this reason, there is now considerable demand for a microprocessor system which can initialize the cache directory by means of hardware, before a program is executed.